介质阻挡放电协同Ag/Al_2O_3对NO_x脱除的影响

为有效去除发电厂烟气中产生的NOx,利用介质阻挡放电(DBD)产生低温等离子体并结合催化剂Ag/Al2O3进行烟气脱硝实验,研究了在加入乙烯的条件下,平均负载量、催化温度和装置的布置方式对NOx脱除的影响。结果表明,随着负载的增多,NO脱除率呈现先增大后减小的趋势,5种负载量中最佳为1.76%;随着催化温度的升高,NO脱除率同样呈现先增大后减小的趋势,最佳的催化温度为150℃左右;3种不同布置方式对NO和NOx脱除有明显差别,单独催化剂在NO和NOx的脱除率都比较低;单独介质阻挡放电NO脱除率很高,但是NOx很却很低;而两者结合在NO和NOx都达到了很好的效果。     

氧活性粒子氧化NO生成HNO_3

采用强电离介质阻挡放电方法制取高浓度氧活性粒子(O+2、O3)并注入气体外排烟道中,实现O+2、O3氧化NO转化成资源酸(HNO3)的等离子化学反应。描述强电离放电的氧活性粒子产生器,讨论烟道中O+2、O3氧化NO成HNO3等离子体反应机制,分析回收酸液的NO-2、NO-3离子种类及浓度。考察强电离放电等离子体源的输入功率、水体积百分比、气体温度、气体流速对NOx氧化率的影响。氧化率为97.2%的最佳实验条件是:O+2浓度为1.38×1010个/cm3,O3浓度为210 mg/L,烟气温度为65℃,H2O体积浓度为5.6%,停留时间为0.94 s。     

湖域工业点源初始排污权配置定额模型与算法研究

针对湖域工业点源初始排污权定额配置问题,以“公平、效率、可行”为配置原则,通过引入权重系数的字典序最小化最大值方法,构建了基于多主体多种初始排污权多期配置的字典序定额模型,并给出求解算法。进而以江苏省太湖流域27类主要工业行业的初始氨氮排污权单期配置为例,从行业初始排污权短缺率与行业治污效益两方面,对比分析了基于等短缺率定额模型、等环境容量比例定额模型、字典序定额模型计算得到的3种定额配置方案效果。结果表明：相对于另外两种定额模型,字典序定额模型所得配置方案可实现平均行业短缺率最小(4613%),平均行业治污效益最大。研究也表明在“公平、效率、可行”配置原则下,字典序定额配置方法能够更为有效的促进企业治污技术提标升级和区域产业结构升级     

不同场地条件下水下隧道周围土体位移变化的数值分析

以拟建的哈尔滨松花江隧道为背景,考虑土体—衬砌的材料非线性特性和相互作用,按平面应变假定,建立在不同场地条件下的若干接近实际的有限元计算模型,应用有限元计算软件ANSYS进行数值分析,得出不同场地条件下隧道周围土体位移的分布规律,遴选出了影响水下隧道周围土体变形的部分关键因素,为合理确定隧道覆土层安全厚度提供了一定的理论依据。     

Inactivation of MS2 bacteriophage by streamer corona discharge in water

Electrical discharge processes are emerging as water treatment technologies applicable to both the degradation of organic contaminants as well as inactivation of pathogens. Particularly as a disinfection technology, electrical discharge processes do not produce toxic byproducts, and effectively inactivate a wide spectrum of microorganisms by multiple lethal actions generated by the formation of plasma channels. This study demonstrates the inactivation of a virus using the streamer corona discharge process (SCDP) with MS2 phage as a surrogate. A rapid inactivation of MS2 phage (i.e., approximately 4 log inactivation in 5 min) was observed in all experimental runs conducted. Discharge conditions such as applied voltage and storage capacitance significantly affected the inactivation efficiency of MS2 phage, whereas the influence of water quality parameters was minor. In order to elucidate the mechanism of MS2 phage inactivation, potentially lethal factors that can be generated by the SCDP were selected, and their roles in the inactivation of MS2 phage were examined. As a result, effects of UV radiation, chemical oxidants, and pulsed electric fields were found to be insignificant. The shockwave generated upon plasma channel formation appears to be the most important factor responsible for MS2 phage inactivation.     

基于博弈论的非点源污染控制模型探讨

随着对工业和城市生活污水等点源污染治理能力的不断增强,农业非点源污染对水质环境的影响日益凸现.相对于点源污染,非点源污染发生的不确定时间、不确定途径、不确定量等特点给治理政策的制定带来很大难度.本文从著名的公地悲剧现象出发,着力从市场博弈及政府监督博弈两个模型分析非点源污染制造者之间的博弈格局,并提出以“集体表现”的形式对非点源污染进行管理和控制.市场博弈模型中以一定的排污削减目标为前提,确定以成本最优的原则进行点源-非点源排污权交易是可行且有效率的;而政府监督博弈模型的结果显示:合理的环境补贴和惩罚机制、政府对自身声誉及公众形象的重视及维护对非点源污染治理起正向促进作用.     

Engineered nanomaterials in rivers--exposure scenarios for Switzerland at high spatial and temporal resolution

Probabilistic material flow analysis and graph theory were combined to calculate predicted environmental concentrations (PECs) of engineered nanomaterials (ENMs) in Swiss rivers: 543 river sections were used to assess the geographical variability of nano-TiO₂, nano-ZnO and nano-Ag, and flow measurements over a 20-year period at 21 locations served to evaluate temporal variation. A conservative scenario assuming no ENM removal and an optimistic scenario covering complete ENM transformation/deposition were considered. ENM concentrations varied by a factor 5 due to uncertain ENM emissions (15%-85% quantiles of ENM emissions) and up to a factor of 10 due to temporal river flow variations (15%-85% quantiles of flow). The results indicate highly variable local PECs and a location- and time-dependent risk evaluation. Nano-TiO₂ median PECs ranged from 11 to 1′623 ng L⁻¹ (conservative scenario) and from 2 to 1′618 ng L⁻¹ (optimistic scenario). The equivalent values for nano-ZnO and nano-Ag were by factors of 14 and 240 smaller.     

Polarity effect of pulsed corona discharge for the oxidation of gaseous elemental mercury

The effect of polarity on the oxidation of Hg⁰ was examined in the presence of O₂ via a pulsed corona discharge (PCD). The experimental result showed no difference in the energy yield of Hg⁰ oxidation at both positive and negative PCDs (∼8 μg Hg W h⁻¹ at following conditions: total flow rate = 2 L min⁻¹ (Hg⁰ = 50 μg N m⁻³, O₂ = 10%, and N₂ balance), temperature = 150 °C, and specific energy density = 5-15 W h N m⁻³). This suggests that the positive PCD process used to control gaseous air pollutants may play an essential key role in Hg⁰ oxidation because it consumes enough energy (∼15 W h N m⁻³) but an electrical precipitator could not because it consumes less energy (∼0.3 W h N m⁻³) to oxidize Hg⁰.     

Contamination of nonylphenolic compounds in creek water, wastewater treatment plant effluents, and sediments from Lake Shihwa and vicinity, Korea: comparison with fecal pollution

Nonylphenolic compounds (NPs), coprostanol (COP), and cholestanol, major contaminants in industrial and domestic wastewaters, were analyzed in creek water, wastewater treatment plant (WWTP) effluent, and sediment samples from artificial Lake Shihwa and its vicinity, one of the most industrialized regions in Korea. We also determined mass discharge of NPs and COP, a fecal sterol, into the lake, to understand the linkage between discharge and sediment contamination. Total NP (the sum of nonylphenol, and nonylphenol mono- and di-ethoxylates) were 0.32-875 μg L⁻¹ in creeks, 0.61-87.0 μg L⁻¹ in WWTP effluents, and 29.3-230 μg g⁻¹ TOC in sediments. Concentrations of COP were 0.09-19.0 μg L⁻¹ in creeks, 0.11-44.0 μg L⁻¹ in WWTP effluents, and 2.51-438 μg g⁻¹ TOC in sediments. The spatial distributions of NPs in creeks and sediments from the inshore region were different from those of COP, suggesting that Lake Shihwa contamination patterns from industrial effluents differ from those from domestic effluents. The mass discharge from the combined outfall of the WWTPs, located in the offshore region, was 2.27 kg d⁻¹ for NPs and 1.00 kg d⁻¹ for COP, accounting for 91% and 95% of the total discharge into Lake Shihwa, respectively. The highest concentrations of NPs and COP in sediments were found in samples at sites near the submarine outfall of the WWTPs, indicating that the submarine outfall is an important point source of wastewater pollution in Lake Shihwa.     

低温等离子体氧化水中难降解有机物研究

实验将介质阻挡放电与电晕放电组合在同一个反应器内,实验废水为直接大红染料溶液,将高压电极上通人50 Hz交流高压电,介质阻挡放电系统的电极间距为30 mm、电晕放电系统电极间距为25 mm、电源电压20 kV,利用常压空气中形成的雾化水电极介质阻挡放电/电晕放电低温等离子体及其活性基团作用于难降解有机物分子.实验分析了...